64 bit guest in a 64 bit host without VT extensions

[calabacin]

I have a 64bit Pentium-D computer with a 64-bit Ubunu and I would like to install a 64-bit guest.

I have been looking around and I'm not quite sure this is possible. Can any one throw some light in this? I've just bought 4GiB RAM and two hard disks in order to do this, only to find out that it may not be possible.

So:
-Is it possible to run 64-bit guests on a 64-bit host without AMDV or VTX extensions?

Just in case, here is the content of my /proc/cpuinfo:

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processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	: Intel(R) Pentium(R) D CPU 3.00GHz
stepping	: 7
cpu MHz		: 2999.981
cache size	: 1024 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts pni dtes64 monitor ds_cpl est cid cx16 xtpr lahf_lm
bogomips	: 5999.96
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 15
model		: 4
model name	: Intel(R) Pentium(R) D CPU 3.00GHz
stepping	: 7
cpu MHz		: 2999.981
cache size	: 1024 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 5
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts pni dtes64 monitor ds_cpl est cid cx16 xtpr lahf_lm
bogomips	: 6000.29
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:

And my uname -a:

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Linux douglas 2.6.28-15-server #52-Ubuntu SMP Wed Sep 9 11:34:09 UTC 2009 x86_64 GNU/Linux

Thanks a lot in advance.

[calabacin]

Guess what, I at last found the reply in the FAQ. I promise I did take a look in a lot of places.

The FAQ:
http://forums.virtualbox.org/viewtopic.php?f=1&t=8669

I fail to see why I need VT-X/AMD-V in order to virtualize the same hardware I have.

[Sasquatch]

Because software virtualizing 64 bit is difficult and very slow to say the least. If you want to have 64 bit Guests so bad, use Qemu. If you don't mind waiting half an hour or more to boot the VM.

[James Bond 007]

Guess what, I at last found the reply in the FAQ. I promise I did take a look in a lot of places.

The FAQ: http://forums.virtualbox.org/viewtopic.php?f=1&t=8669

I fail to see why I need VT-X/AMD-V in order to virtualize the same hardware I have.

Basically, in virtualization you will not be able to "use" the same hardware in your virtual machine. The virtual machine presents another set of hardware for your guest operating system to see. And as Sasquatch says the 64-bit virtualization is very slow without the assistance of hardware virtualization in the CPU. It is the same way with other virtualization software such as VMware Workstation (which I use) or Parallels.

By the way, if you are still using a Pentium D CPU, it is quite possible your motherboard (specifically the chipset) will not be able to support 4GB RAM even though your CPU is 64 bit. If you wish to be able to enjoy the full benefits of 64 bit virtualization, you may need to upgrade your motherboard and CPU to more recent versions such as the Intel Core 2 Duo or Core 2 Quad together with a P43/P45 motherboard.

[charlau]

I know this is an old post, but pentium M processors are still around (I'm writing this on one!). In my case, I was trying to open a windows 8-64 bits virtual machine on my PC host with Windows 8-64 bits. I have a HP Pavillion x360 circa 2014, with the Pentium N3520 CPU. Turns out virtualization is turned OFF by default in the BIOS. It says HP recommends to have it OFF if we don't use virtuallization... (I find this strange but anyway).

Once turned on, Virtualbox gave me back to option of changing in the settings to a 64 bits version of the guest (that's important, if you just enable virtualization and don't change the setting, it still won't work).

So I'm a happy camper now!